The present invention relates to a forceps device for use in an endoscope.
Such a forceps device is shown in FIG. 1 and comprises a forceps or clamp member which is so operated that it is inserted into an entrance aperture 3 provided at an operating portion 2 of an endoscope 1 and projected from an exit aperture 7 provided at an end portion 6 of the endoscope 1 through at least one channel (not shown) formed in a connecting portion 4 and a bend portion 5 of the endoscope, thereby performing desired object.
As shown in FIGS. 1 and 2, the forceps device comprises a flexible tube 10 capable of being inserted into the channel of the endoscope 1, an operating portion 11 provided at a base portion 10a of the tube 10, a forceps head 12 provided at a tip portion 10b of the tube 10, and a pair of forceps cups 8 forming the forceps and provided to the head 12 in a manner capable of opening and closing.
Each forceps cup 8 has a connecting portion 8a and a connecting extension 13 which is connected through a link 14 to a wire coupling 16 connected to a tip 15a of an operating wire 15 which is extended through the tube 10, and hence coupled to the operating wire 15.
The operating wire 15 has a base portion (not shown) which is connected to an operating column 17 of the operating portion 11.
When the column 17 moves backward and forward the wire 15 can be moved backward and forward in the tube 10 and thus the pair of forceps cups 8 can be closed and opened about a connecting pin 19 provided to a cover 18 having a slitted opening of the head 12 as a fulcrum.
The pair of forceps cups 8 of the device 9 are so constructed that the extension 13 provided to the connecting portion 8a of cups 8 is connected to the link 14 by first connecting pin, the link 14 is connected to the operating wire 15 through the coupling member 16, and the connecting portions 8a of the cups 8 are connected to each other and to the cover 18 having slitted opening which is provided to the head 12 in a manner capable of closing and opening.
Connecting means of these components is described hereinafter with respect to FIGS. 3a and 3b as well as FIGS. 4 and 5. As shown in FIG. 3a, a butting portion 13a of the extension 13 is butted to the link 14, an aperture 13b of the extension 13 is registered to an aperture 14a of the link 14, and a connecting pin 20 is inserted into and fitted in the registered apertures 13b and 14a.
The pin 20 has a length longer than that l.sub.1 equal to a sum of thickness of the extension 13 and the link 14 so that a head portion 20a of the pin 20 and the side surface of the link 14 become coplanar after fitting the pin 20 in the apertures 13b and 14a and a tip portion 20b of the pin 20 is projected from the side surface of the extension 13.
The projected tip portion 20b of the pin 20 is, then, caulked to cause plastic deformation resulting in a formation of caulked portion 20c so that the pin 20 is held in the apertures 13b and 14a and thus the extension 13 and the link 14 are rotatably connected to each other by the pin 20 (refer to FIG. 3b).
As shown in FIG. 4, then, both links 14 are butted to a butting portion 16b of the coupling member 16, an aperture 14b of the link 14 is registered to an aperture 16a of the coupling member 16, and a connecting pin 21 is inserted into and fitted in the apertures 14b and 16a, thereby connecting links 14 to the coupling member 16 and thus the operating wire 15.
The pin 21 has a length longer than that l.sub.2 equal to a sum of thickness of the coupling member 16 and both links 14 so that a head portion 21a of the pin 21 and the side surface of one link 14 become coplanar and a tip portion of the pin 21 is projected from the side surface of the other link 14 after fitting the pin 21 in the apertures 14b and 16a. The projected tip portion of the pin 21 is caulked to cause plastic deformation resulting in a formation of caulked portion 21c so that the pin 21 is held in the apertures 14b and 16a and thus the coupling member 16 and both links 14 are rotatably connected to each other by the pin 21.
As shown in FIG. 5, in order to connect both forceps cups 8 to the cover 18 having a slitted opening of the forceps head 12, the connecting portions 8a of both cups 8 are inserted in the slitted opening of the cover 18 and thus both links 14 connected to the portions 8a and the coupling member 16 connected to both links 14 are also inserted in the slitted opening.
Then, apertures 8b of both connecting portions 8a are registered to apertures 18a of the cover 18 and a connecting pin 22 is inserted in the registered apertures 8b and 18a.
The pin 22 has also a length longer than that l.sub.3 equal to an outer diameter of the cover 18 so that a head portion 22a of the pin 22 and the side surface of the cover 18 become coplanar and a tip portion of the pin 22 is projected from the side surface of the cover 18 after fitting the pin 22 in the apertures 8b and 18a. The projected tip portion of the pin 22 is caulked to cause plastic deformation resulting in a formation of caulked portion 22c so that the pin 22 is held in the apertures 8b and 18a and thus both forceps cups 8 and the cover 18 are rotatably connected to each other by the pin 22.
As described above, the connection of respective components are performed by the caulked portions 20c, 21c and 22c of connecting pins 20, 21 and 22 so that caulking operation becomes complicated. In addition thereto it is necesssary to file respective caulked portions 20c, 21c and 22c during working in order to make these portions 20c, 21c and 22c coplanar with surfaces of the extension 13, the link 14 and the cover 18, respectively. It is also necessary to adjust respective components and variation of quality for respective workers since operating conditions of respective connecting portions are dependent on connecting conditions of respective pins 20, 21 and 22.